Automatic electric switch



' Aug. 5, 1930. c. E. HANNY I AUTOIATIC ELECTRIC SWITCH Filed July 21,1928 NVENTOR have been far from person knowing little of such .both'lifeand pro 5 lessly add Patented A1155, 1930 A UNITED STATES PATENT OFFICEcmnms 12.3mm, or UNIONVILLE, CONNECTICUT, assrenon 'ro 'rma 'rnmm-ELEC'1BIG MANUFACTURING COMPANY, or (PLAINVILLE, CONNECTICUT, A coarom-TION OF CONNECTICUT Application filed July 21,

Switches of this type have usuall consisted' of a metal box havin ahinge cover and enclosingfa switch and ses and having an external operting handle.

The covers oft ese boxes have usually been merely latched in closedposition so as to permit the ready opening ofthe same by the genant inorder to insert or replace blown uses. I

The results of this typeof construction satisfactory because, for

instance, the entire switch construction be- -i ng free of access, thetenant is strongly tempted to over-fuse the installation or to add newcircuit lines and thus overload the circuit to such an extent that thefuse receptacles or clips cannot receivefuses of large I I enoughcapacity to properly protect the circuit. In the event of the sesblowingrepeatedly, the tenant is strongly tem ted to bri ge the.

(and sometimes actually does fuse terminals with coins or ot er. metalobjects, thus endangering not only'the various electric devices in thecircuitbut also causing a tremendous fire-risk by the over-heating atimperfect joints, short of wires, arcing circuits, etc.

Further, the tenant, in most instances, must furnish his own fuses and,the average I matters, may purchase fuses ofsuchsmall capacit that theywill'blow repeatedly or he maymstaIl fuses of greater capacity than theinstallation is intendedto-carry and thus endanger erty. "In-these days,0 the rapidly increasing introduction of new electrichousehold-andoffice devices, it is the rule rather than the exception, or the generalpublic to thoughta more and more newdevices and attach them in one wayor another to circuits which may already be loaded to maximum capacity.Thusit' is highly desirable that general public use in residences,

au'romrrc nnnc'rmc swrrcn 1922. semi m. 294,518.

locked box and having an external handlefor normal manual operation, theautomatic (por- 4 tion of the construction bein calibrate centralservice station attac s and being normally inactive but 'functionin toentirely open the circuit on overload of s ort circuit conditions.

My invention aims to provide the combination of a manually operatedswitch for normal operation and a normally inactive automaticallyoperated auxiliary switch for protection against overload or shortcircuits.

One object of my invention is to provide an enclosed switch constructionhaving. an external operating handle, a manually operable switch fornormal operation and a normally inactive auxiliary switch ada ted toautomatically open the circuit on either a gradual overload, a suddenexcessive surge in the circuit or a short circuit.

Another object is to provide an automatic safety switch of fuses orother replaceable parts and which may be calibrated by the centralstation employees and then locked or sealed so as to which will notreqmre the use prevent access to any of the switch parts or 7 terminalsby the current consumer.

Another object is to provide a construction of thischaracter which willhave sufiicient time lag to prevent the automatic operation of theswitch by the usual surge in the circuit caused by the initialclosingmovement of the switch.

Another object is to provide, in a construction' of this character, acombined heater unit and electromagnet so associated with a bimetallicthermostatic latch "as to cause the automatic' operation of thelatch'but. without any current flowing through the latch.

. Another object is to provide a combined heater and electro-magneticcoil of the? receding descri gsion directly in the circultto becontrolled ut of such carrying capacity .as-to ofier practically noresistance to a nor- Neither ofthe switch members need be of any exacttypebut I have chosen to inco rate my invention a construction. sim: atto that shown in the Getchell Patents Nos.

1,677,331 and 1,677

loo

Detailed descriptions and difierences e be further disclosed as thespecification pro.-

' ceeds.

In carrying out the invention in the prean auxiliary contact. Thisquick-break ferred manner, I provide aninsulating housing which carriesthe various conducting element's. [The latter includes a manuallyoperable main switch for normal'operation and Ya quick break switch forautomatic'operation, the automatic switch preferably having switch isheld in closed circuit position by means of a latchwhich is not includedin the electric circuit but which is adapted to be thermostaticallyoperated by reason of a gradually increasing overload and which isadapted also to be instantaneously operated; electro-magnetically by asudden excessive overload.

The unit which includes the housing, the

switch and the latch mechanism is adapted 'to one form of apparatusembodying my inven tion, showing the manual and automatic switches inthe open circuit positions in full lines and, in dot and dash lines,showing the inanually operable switch member, and the automatic switchmembers in position for resetting the automatic switch. Fig. 2 is anexploded perspective view of parts of the switc static latching memberengaged with a part of the automaticfi'switch member to latch the lattermember in closed circuit position. The stationary 5 is secured to theinsulating body or ousing 6 by means of a screw 7, and supports the mainswitch blade 8 on the pivot pin 9. The stationary contact or 'aw 10 ofthe switch is secured to the body 6 y screw 11 which erably adapted tobe manually operated by means of a crank arm 01f rod'.13junder allnormal'conditions.

The circuit terminal 14 is secured to the opposite end oftli insulatingbody 6 by a screw The stationary contact plate 16 is secured to the body6 by means of a-screw 17. The

bracket 1 8 is secured to the insulating body by means of screws 15 and17 1 The movable contact member 19 is pivot ally supported ,by an arm ofthe frame 20' which is in turn carried'byfthe pivot pin 9.

' .The arm 21 is also pivoted on pin 9 and is embodying my invention.Fig. 3 is a detail view showing the thermo-' aflso secures in place theline terminal 12. The switch blade 8is prefprovided with a contactroller 22 adapted to coact' with the contact plate 16.

The cross bar 24 which is secured tothe arms 21 is electricallyconnected by strip 25 to the stationary switch base 5. The contactmember'19is similarly connected by a flexi ble strip26. a

A spring 27 is interposed between the insulating body 6 and the rear endof the contact member 19 so as to apply pressure tending to move the twomovable switch contact members 19 and 22 awayfrom the stationary contactplate 16. v I I :A pin 28 connected to the contact member 19 extendsthru the cross bar 24 and is surrounded by a-spring 29 which tends todraw the contact member 19 toward the arm 21-.

The bimetallic thermostatic latching member 30 is rivetted or otherwisesuitably secured to bracket 18 and has its movable endadapted to engagethe latch'carried by the tilting frame 20. This latch has an abutment 31and a movable abutment 32. A screw 33 serves as a convenient means foradjusting or calibrating the abutment 32 which projects more or lessbeyond the abutment 31, thus making 1t possible to adjust thesensitivity or point of release ofthe thermostatic member ,To reset theswitch or close the circuit from the position shown in Fig. 1 themanually operable switch blade 8 is moved toward the dot and dashposition. The pressure of the switch blade 8 against the cross pin 35 ofthe tilting frame 20 moves the frame to the dotand dash position'ofFig. 1. 'Ilhiscompresses the sprin 27 and forces the lefthand end of themova 'le switch member 19 into engage: ment with the stationary contactplate 16.

This movement also carries with it the pin 28 and compresses the spring29 so as to move the contact arm 21 and bring the contact roller 22 intoengagement with the stationary contact plate 16, thus placlngboth of thesprings 27 and 29 in compression.

This movement brings the tip of the latch 32i3nt0 engagement with thetip of the thermostatic member 30 as shown in Fig. 3 and thus'latchesthe members of the automatic switch in the closed circuit position.

When the auxiliaryswitch is latched in closed circuit-position themanually oper- -able knife blade switch 8 may be closed and the entirecirciiit completed thru. the elements12, 10,8, 5, 25 and 26, 22 and 19,16, 17, 18,42, 40, 41, 15 and 14. Obviouslythe -.circuit can be openedmanually when desired by moving the switch blade 8.

In serieswith the circuit thru the switch is the coil 40, the terminalplates of which,

41 and 42, are separated by an insulating washer43. This coil ispreferably covered with asbestos insulating material so as to insulatethe, individual coils and to retain the eat.

The two elements and 45 constitute re spectively the armature and thecore of the preferably bar free to warp or bend when heated.

. The core member 45 may be secured to the insulating cover 46.. Thelatter is preferably "provided with a hood-like '10 portion 47 having arecess or pocket 47 which surrounds the coil 40 but preferably leavingsome open spacefor the radiation of the heat from the and coil.Preferably this cover 46 and the hood- 47 are formed of insulatingmaterialof an asbestos character and the pocket isso posi tioned as toconcentrate the heat of the coil adjacent the bendable portion of thebimetal lic thermostat member 30.

The cover 46 may. place for instance b extending -thru anc carriedthereby. I

.Incase the circuit is slowly overloaded the coil 40 will heat up theadjacent thermostatic bar 30 and release its tip from the latch 32 thusallow the switchto open automatically. In case the circuit is suddenlyandexcessively overloaded the magnet coil 40 will instantaneously drawthe armature-'44 toward the core and bend the bar 30 so as I. thecircuit.

set or calibrated, the

' common enclosed to release the switch and automatically open Byadjusting the screw 33 the switch may be calibrated to openautomatically under any desired overloadcondition;

After the auxiliary switch has once been sealed and then, sofarasthe-current consumeris concerned, the device-is positively limited tocarry only a certain predetermined load and will automaticall openthecircuit as soon and as often as t e predetermined capacity is'exceededand regardless of any attempt to prevent or delay the automaticoperation. g

.It will be noted that, in this construction,- the noil'lmal operationrequires nothing more than t e manual operation of the switch 'ablad in-exactly the same, manner as a thejlil tomatic auxiliary switch isadapted to remain closed at alLtimes except when automatically releasedlatch or y either the thermostatic the.electro magneticcoil.

b When-tile auxiliary switch has been opened "lautomaticall ,itJinai bere-set or are-latched by the simp e switc opening movement of the blade8,.but the -complete circuit cannot be re stablished untilthe auxiliaryswitch has first beenre-latched in this manner, after which the mainblade 8 may be closed tocompletefth'e circuit. This last feature is ofgreatimportance because the auxiliary switch contacts are 'ofthebutttype and,

assemble the parts, H duced and, by reasonof there being fewer besuitably secured in a number of screws 48' orage members 49 into thebody 6 or some element such as a nutstatic latch for said box may belocked or main switch member,

tion-abetivveen the switch for the reason that switch an tages of thisare that there can be no arcing at the'latching point as the latch isreleased-- there is no danger of injuring the latcn'by a short-circuitor excessive overload-the number of electrical joints is reducedfeweroperations are therefore the cost( is reparts, the device ismoredependable because there is less likelihood of the parts movin thusdisturbing the cahc or loosening and bration to which the device hasbeen set.

I claim: v 1. A switch including an insulatin housing, a movable switchvmember, a t ermoswitchmembe'r', a stationary coil'enclosedin saidhousing adjacent said latch for heating and bending said latch I and formagnetical attracting said latch to release saidmovable switch member.

2. A switch including 'an insulating body, a movable switch membersupported thereby,

athermostatic latch member for said switch member and having a magneticarmature secured thereto, a heat'retaining cover for said body, andacoil enclosed by said'body and cover for heating said latch member andbeing concealed from the operators vision,

required to produce and also for magnetically attracting said armature"on predetermined overload conditions in the cover in and a core member-secured proximity to said armature.

3. A switch including a manually operable an auxilia member, in-seriestherewith, a 'catc for the auxiliary switch member,a bendablethermostatic latch for holding said catch andsaid switch auxiliaryswitch member means of connecberwhereby said catch maybe reset by theaction of the manually member, and a coil for electro-maghetically andfor-thermally-bending said latch to release saidauxiliary switch. a r

The combination in a quick break switch of a spring-pressed switchmember, a bendable thermostatic latch for holding said .switch' memberin closed position and an in series with said operable main switch latchbeingroperable both ther manual] operable main y I switch member and theauxi 'ary switch membeing entirely free of circmt v 5. The combinationwith a quick-break and closing switch of a thermally bendable elementfor latching said switch in closed position and a magneticallyoperablerelease device having a coilin' electrical circuit with, said switch forheating said element and having an armature directly associated withsaid element and cooperating with said coil to release said switch onexcessive overload in the circuit,

the said bendable latch being normally free of direct contact with saidcoil.

6. The combination'in a quick-break switch of a bendable bimetalliclatch normally holding the switch in a closed circuit position, anelectro-magnet ..coil in series with the I switch for automaticallyheating and benda circuit, a bimetallic latch mem her in said recess forholding the switch,

mechanism in its closed circuit condition, an

armature member secured to the latchmemher, and a stationary coilserving to warp the latch when heated and serving to magneticallyattract said armaturewhen quickly overloaded.

. CHAR ES. E. 111m.

-' ing said latch to releasethe switch on an ordin overload, and anarmature carried by said a'tch and adapted to be attracted by saidmagnet in the event of an excessive overloadin the circuit the-saidbimetallic latch and said armature said soil. I 7. The combination in aswitch of a movable switch member, a spring for moving I saidswitch-member to open position, a bend= said auxiliary switch in closedposition, a magnetic (soil for thermally bending said latch to releasesaid auxiliary switch and for electro-magnet-ically bending said latchto release said auxiliar switch, the said bendable latch being inependent of the circuit and free of allcircuit winding.

9. In a switch construction the combination of a pivoted frame, .aspring-pressed being normally free from 7 contactmemberv hinged to saidframe, asec. .ondary pivoted contact member, a resilient? connectionbetween said contact members providinglimited relative movement betweenthe same, a'latch member coacting withsaid frame to hold said frame andits contact members in closed circuit position, a -cornbinedelectro-magnet and heating "coil for "longed overload, and for.disengaging said latch memberon a sudden predetermined ex-.

' cessive overload. 1

10. A switch construction comprising an insulating bod having a recess,snap action switch mechamsm having manually operable -'means on one sideof the body. for opening "disengaging said latch member on a prov

